MOTION DETECTION IN MEDICAL SYSTEMS

• US 20110251478A1
• Filed: 08/06/2008
• Published: 10/13/2011
• Est. Priority Date: 08/10/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Wieczorek, Herfried K.
• Granted Patent: US 8,386,011 B2
• Time in Patent Office: Days
• US Class Current: 600/411
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61B 2090/3945 Active visible markers, e.g. light emitting diodes
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/706 Indicia not located on the patient, e.g. floor marking
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers

Abstract

In a medical system, at least one medically operative member (10, 12, 100) is configured to interact with or acquire data from a subject (74) disposed in an examination region. An array of photosensors (70, 170) is disposed on the at least one medically operative member. The array of photosensors is arranged to view the examination region. A position-determining member (82, 82a, 82b) is configured to determine a position of at least one optically detectable marker (72, 172) disposed with the subject in the examination region based on light from the at least one optically detectable marker sensed by the array of photosensors.

Claims

1. A position measurement system comprising:

an array of photosensors configured to be disposed on a medically operative member configured to interact with or acquire data from a subject disposed in an examination region, the array of photosensors arranged to view the examination region; and

a position-determining member configured to determine a position of an optically detectable marker disposed with the subject in the examination region based on light from the optically detectable marker sensed by the array of photosensors.

2. The subject detection system as set forth in claim 1, further comprising:

said at least one optically detectable marker configured to be disposed with the subject in the examination region.

3. The subject detection system as set forth in claim 2, wherein said at least one optically detectable marker comprises a light emitting marker.

4. The subject detection system as set forth in claim 1, further comprising:

a collimator disposed between the array of photosensors and the examination region, the position-determining member determining a position of a optically detectable marker based on light from the optically detectable marker sensed by the array of photosensors and defining optical projection data.

5. The subject detection system as set forth in claim 4, wherein the array of photosensors provide optical projection data for the optically detectable marker from at least two different angles, and the position-determining member determines the position of the optically detectable marker based on an intersection of optical projections of different angles.

6. The subject detection system as set forth in claim 1, wherein the photosensors of the array of photosensors have viewing angles effective for a substantially contiguous group of photosensors of the array of photosensors to simultaneously sense light from the optically detectable marker, and the position-determining member determines the position of the optically detectable marker based on relative light intensities sensed by the photosensors of the substantially contiguous group of photosensors that sense light from the optically detectable marker.

7. The subject detection system as set forth in claim 1, further including said medically operative member, wherein said medically operative member comprises at least one detector head including an array of radiation detectors and a collimator disposed between the array of radiation detectors and the examination region, the array of photosensors being configured to be disposed one of (i) between the collimator and the array of radiation detectors, and (ii) on a face of the collimator proximate to the examination region.

8. A medical system comprising:

at least one medically operative member configured to interact with or acquire data from a subject disposed in an examination region;

an array of photosensors disposed on the at least one medically operative member, the array of photosensors arranged to view the examination region; and

a position-determining member configured to determine a position of at least one optically detectable marker disposed with the subject in the examination region based on light from the at least one optically detectable marker sensed by the array of photosensors.

9. The medical system as set forth in claim 8, further comprising:

said at least one optically detectable marker comprising a light-emitting marker configured to be disposed with the subject in the examination region.

10. The medical system as set forth in claim 8, wherein the at least one medically operative member comprises:

at least one radiation detector having a radiation-sensitive face configured to detect radiation of interest, the array of photosensors being generally planar and arranged parallel with the radiation-sensitive face.

11. The medical system as set forth in claim 10, further comprising:

a collimator mounted on the radiation-sensitive face of the at least one radiation detector and disposed between the generally planar array of photosensors and the examination region to collimate both radiation of interest and light such that radiation of interest detected by the radiation-sensitive face defines projection data and light sensed by the generally planar array of photosensors defines optical projection data, the position-determining member comprising electronics configured to reconstruct the optical projection data to determine the position of the at least one optically detectable marker disposed with the subject.

12. The medical system as set forth in claim 11, wherein the at least one radiation detector comprises a plurality of movable detector heads and the electronics are configured to reconstruct the combined optical projection data from the generally planar arrays of photosensors disposed on the radiation-sensitive faces of the plurality of detector heads.

13. The medical system as set forth in claim 10, further comprising:

a collimating microlaminated optical filter disposed between the generally planar array of photosensors and the examination region to collimate a viewing angle of the photosensors such that light sensed by the generally planar array of photosensors defines optical projection data, the position-determining member comprising electronics configured to reconstruct the optical projection data to determine the position of the at least one optically detectable marker disposed with the subject.

14. The medical system as set forth in claim 10, wherein the photosensors have a viewing angle effective for a substantially contiguous group of photosensors of the array of photosensors to simultaneously sense light from a nearby optically detectable marker, and the position-determining member comprises:

electronics configured to determine the position of the nearby optically detectable marker based on relative sensed light intensities of the substantially contiguous group of photosensors of the array of photosensors.

15. The medical system as set forth in claim 8, wherein the at least one medically operative member comprises:

a medical imaging system including a generally cylindrical bore surrounding the examination region, the array of photosensors being disposed on an inner surface of the generally cylindrical bore so as to view the examination region.

16. The medical system as set forth in claim 8, wherein the at least one medically operative member is selected from a group consisting of:

(i) a detector head of a gamma camera, the array of photosensors being disposed on a radiation-sensitive face of the detector head;

(ii) a magnetic resonance (MR) scanner, the array of photosensors being disposed on a bore of the MR scanner;

(iii) a positron emission tomography (PET) scanner, the array of photosensors being disposed on a detector ring of the PET scanner; and

(iv) a radiation therapy system, the array of photosensors being disposed on or in fixed spatial relation with a radiation emissive member of the radiation therapy system.

17. The medical system as set forth in claim 8, wherein the array of photosensors comprises one or more arrays of amorphous silicon-based photosensors.

18. The medical system as set forth in claim 8, further comprising:

a collimating member disposed between the array of photosensors and the examination region to collimate a viewing angle of the photosensors such that light sensed by the array of photosensors defines optical projection data, the position-determining member comprising electronics configured to determine the position of the at least one optically detectable marker based on the optical projection data.

19. The medical system as set forth in claim 8, wherein the position-determining member comprises:

electronics configured to determine the position of the at least one optically detectable marker based on analysis of light intensities sensed by a contiguous group of photosensors of the array of photosensors.

20. The medical system as set forth in claim 8, wherein the at least one medically operative member comprises:

a medical imaging system configured to collect data from the subject and an image reconstruction member configured to reconstruct an image of at least a portion of the subject based on the collected data, the image reconstruction member further configured to adjust at least one of the collected data and the reconstructed image based on subject position inferred from the optical marker position of the at least one optically detectable marker determined by the position-determining member.

21. The medical system as set forth in claim 8, wherein the at least one medically operative member substantially occludes from view at least a relevant portion of the subject with which the at least one medically operative member is configured to interact or from which the at least one medically operative member is configured to acquire data.

22. The medical system as set forth in claim 8, wherein the at least one medically operative member is configured to move respective to the subject during operation of the medically operative member, and the array of photosensors disposed on the at least one medically operative member moves in fixed relative spatial relationship with the at least one medically operative member during operation of the medically operative member.

23. A position measurement method comprising:

detecting at least one optically detectable marker disposed on a subject in an examination region using photosensors disposed on a medically operative member configured to interact with or acquire data from the subject in the examination region; and

determining at least one optical marker position corresponding to the at least one optically detectable marker based on the detecting.

24. The position measurement method as set forth in claim 23, further comprising:

adjusting at least one of (i) data acquired from the subject and (ii) an image reconstructed from data acquired from the subject based on subject position inferred from the at least one optical marker position.

25. The position measurement method as set forth in claim 23, further comprising:

repeating the detecting and determining a plurality of times to track motion of the at least one optical marker position over time.